To steam green beans, place them in a steamer basket over boiling water and cover with a lid. Steam for 5 minutes until they are crisp-tender, drain in a colander, and plunge them into a big bowl of ice water to stop their cooking.
While the green beans are cooking, zest a lemon.
When the green beans are cool, pat them dry with paper towels.
Heat the butter and garlic in a large skillet over medium heat. When the garlic starts to sizzle, sauté for 1-2 minutes until fragrant and lightly golden.
Increase the heat to medium-high and add the green beans. Toss the beans with the garlic and cook for about 2 minutes, stirring occasionally, until the beans are tender and heated through.
Remove the skillet from the heat and stir in the chopped parsley, then sprinkle the grated parmesan cheese and lemon zest over the green beans. Gently toss, allowing the cheese to melt slightly from the heat of the beans.
Season with salt and black pepper to taste, then transfer to a serving dish and serve hot.
Notes
Storage and ReheatingStore leftovers in an airtight container in the refrigerator for up to 3 days.When reheating, green beans can be warmed in the microwave for a few minutes, depending on the quantity. Or, heat a small skillet and add the green beans, cooking for a few minutes until heated through. If they seem dry, you can add a little butter for extra moisture.To Make Ahead
You can blanch the green beans a day ahead of making the final dish. Store them in the refrigerator until needed, then finish the recipe when ready to serve.